Medical radiation device

ABSTRACT

A radiation medical device, including a main support, and a radiation assembly ( 30 ) and an imaging assembly ( 20 ) respectively located at both ends of the main support. After an imaging scan is completed and pathological tissue positioning pictures are taken, a patient is directly moved to the other end of the main support to allow the radiation assembly ( 30 ) to perform radiation therapy to improve the efficiency of the radiation therapy after the completion of pathological tissue positioning, and effectively reduce movement of the patient when the patient is being moved for radiation therapy after the imaging assembly ( 20 ) completes pathological tissue positioning, thus reducing pathological tissue positioning error caused by too much movement.

CROSS REFERENCE TO RELATED APPLICATION

This application is a continuation of U.S. application Ser. No.15/036,799, filed on May 14, 2016, which is a U.S. national stageapplication of International Application No. PCT/CN2014/091001 entitled“Radiation Medical Device,” filed on Nov. 13, 2014, designating theUnited States of America and published in Chinese on May 21, 2015, whichin turn claims priority of Chinese Patent Application No. 201320718512.2entitled “Medical Radiation Device” filed before the State IntellectualProperty Office on Nov. 14, 2013, the contents of each of which arehereby incorporated by reference in its entirety.

TECHNICAL FIELD

The present application relates to mechanical field, and moreparticularly, relates to a radiation medical apparatus.

BACKGROUND

Radiation therapy is a therapeutic method using radiation rays, such asα, β, or γ rays generated by radioactive isotopes, or using X-rays,electron rays, proton rays or other particles generated by various X-rayradiotherapy apparatuses, to impinge diseased tissues of a body. Inmodern medical therapeutic methods, radiation therapy is widely used infields such as tumor therapy, etc.

For example, a medical linear accelerator system is a commonly usedparticle accelerating apparatus for radiation therapy. A medical linearaccelerator includes a treatment head in which a radiation source isarranged for irradiating a diseased tissue.

Besides a series of components such as an accelerating tube, an electrongun, movable targets, a magnet-deflection system, a collimator, aflattening filter, etc., the treatment head further includes ahigh-density shielding layer made of lead for preventing extra radiationrays emitted from the radiation source from irradiating a body during anoperation of the linear accelerator, and thus the treatment head has alarge mass. The linear accelerator is also provided with counterbalanceweights to offset the overturning torque of the treatment head, and thusthe volume of an existing linear accelerator is large, which results introubles for installation, transport, calibration, and maintenancethereof.

Additionally, during a radiation therapy, besides the linear acceleratorgenerating radiation rays, an imaging apparatus, such as a computedtomography (CT) scanner, is also needed to cooperate with the linearaccelerator to position the diseased tissue of a body.

Accordingly, during a radiation therapy, the diseased tissue of apatient needs to be positioned via the CT, and then the patient is movedto the linear accelerator to receive the radiation therapy to thediseased tissue, since both the linear accelerator and the CT scannerhave large volumes, the distance the patient needs to be moved is large,and the course of the movement is complicated, which easily results inerrors in positioning.

Therefore, the problems need to be solved by one person skilled in theart are how to reduce the complexity of a treatment course, to improvethe efficacy of a radiation therapy, and to reduce positioning errorsduring positioning a diseased tissue and irradiating the diseasedtissue.

SUMMARY

A medical radiation apparatus is provided by the present disclosure toreduce complexity of a treatment course of a radiation therapy and thusimprove the efficacy of the treatment, and to reduce positioning errorsduring positioning a diseased tissue and performing the radiationtreatment on the diseased tissue.

In order to solve the above problems, the medical radiation apparatusprovided by the present disclosure includes: a main frame, and a CTassembly and a radiation assembly respectively positioned on an end ofthe main frame along a first axial direction; the radiation assemblyincludes a treatment head, rotatable around the first axial direction,for emitting radiation rays; the CT assembly includes a ray tube and adetector that are in an opposing arrangement and respectively positionedon one side of the first axial direction and rotatable around the firstaxial direction.

Alternatively, the main frame includes a cylindrical body definingopenings on both ends thereof, the first axial direction being a centralaxis of the cylindrical body; the treatment head is fixed onto one endof the cylindrical body, and the CT assembly is positioned on the otherend of the cylindrical body.

Alternatively, the ray tube and the detector of the CT assembly arefixed onto an inner wall of the cylindrical body.

Alternatively, the CT assembly includes a CT stator fixed onto thecylindrical body, and a CT rotor mounted on the CT stator; and the CTrotor is rotatable around the first axial direction, and the ray tubeand the detector are mounted on the CT rotor.

Alternatively, the CT stator is fixed onto an inner wall of thecylindrical body, and includes a mounting hole defined along the firstaxial direction; and the CT rotor mounted on the CT stator via abearing.

Alternatively, the main frame includes a couch plate movable along thefirst axial direction to pass through the openings on both ends of thecylindrical body; the CT rotor includes a through-hole defined along thefirst axial direction, and the ray tube and the detector are positionedon the opposite sides of the through-hole, and the couch plate ismovable to pass through the through-hole.

Alternatively, the CT stator further includes a CT driving mechanism fordriving the CT rotor to rotate; the CT driving mechanism includes afirst motor, a first driving wheel coupled to the first motor, and afirst driving belt coupled between the CT rotor and the first drivingwheel.

Alternatively, the main frame includes a base for supporting thecylindrical body thereon, and the base is provided with a roller drivingmechanism for driving the cylindrical body to rotate.

Alternatively, the roller driving mechanism includes a second motor, asecond driving wheel coupled to the second motor, and a second drivingbelt wrapping around the second driving wheel and the surface of thecylindrical body.

Alternatively, the roller driving mechanism further includes a guidewheel arranged on the base.

According to other embodiments of the present disclosure, a medicalradiation apparatus provided herein includes: a main frame, rotatableabout the central axis thereof; a treatment head, connected with themain frame, for emitting radiation rays; an imaging assembly, definingan imaging through-hole, to image an object located within the imagingthrough-hole, wherein the imaging assembly is connected with the mainframe and rotates along with the main frame.

Alternatively, the main frame includes a cylindrical body substantiallycoaxial with the imaging through-hole.

Alternatively, the medical radiation apparatus further includes a rotorwhich the imaging assembly is mounted on, and is connected with the mainframe and rotates along with the main frame.

Alternatively, the rotor defines the imaging through-hole, and the mainframe includes a cylindrical body substantially coaxial with the imagingthrough-hole.

Alternatively, the medical radiation apparatus further includes: astator of the imaging apparatus, connected with the main frame androtates along with the main frame; and a bearing, connected with therotor and the stator of the imaging apparatus; wherein the rotor isrotatable via the bearing independent of the stator of the imagingapparatus and the main frame.

Alternatively, the imaging assembly is rotatable around the imagingthrough-hole independent of the main frame.

Alternatively, the imaging assembly is located within the interior ofthe main frame.

Alternatively, the imaging assembly is located at least partially withinthe interior of the main frame.

According to other embodiments of the present disclosure, a medicalradiation apparatus provided herein includes: a main frame, rotatableabout a central axis thereof; a treatment head, connected with the mainframe, for emitting radiation rays; a stator of an imaging apparatus,connected with the main frame and rotates along with the main frame; arotor, defining an imaging through-hole and equipped with an imagingassembly, wherein the imaging assembly is used to image an objectlocated within the imaging through-hole; and a connecting component, forconnecting the stator of the imaging apparatus to the rotor, wherein therotor is rotatable independent of the stator of the imaging apparatusand the main frame.

Alternatively, the rotor does not rotate along with the main frame.

Alternatively, the connecting component includes a bearing.

Alternatively, the main frame includes a cylindrical body substantiallycoaxial with the imaging through-hole.

Alternatively, the stator of the imaging apparatus and the rotor arelocated at least partially within the interior of the main frame.

Alternatively, the stator of the imaging apparatus and the rotor arelocated completely within the interior of the main frame.

As compared with prior art, the technical solutions of the presentdisclosure have following advantages:

Positioned at the two ends of the main frame of the medical radiationapparatus are the radiation assembly and the imaging apparatus assembly(for example, a CT assembly), so that a patient can be directly moved tothe other end of the main frame to perform radiation treatment by theradiation assembly after the patient is imaged and the diseased tissueis imaged and positioned, thereby improving the efficiency of theprocedure of performing radiation therapy after a diseased tissue ispositioned, and additionally a positioning error of the diseased tissuecaused by excess motion between when the diseased tissue is positionedand when the diseased tissue is subject to radiation treatment can beeffectively reduced; moreover, the radiation assembly and the imagingapparatus assembly are respectively arranged on one end of the mainframe and can be served as counter balance weights for each other tobalance the overturning torque caused by the large masses thereof, whicheffectively reduces the volume of the medical apparatus, and thereforefacilitates installation, transport, calibration, and maintenance of themedical apparatus.

Further, the main frame includes a cylindrical body, and the imagingapparatus assembly and the radiation assembly are positioned on the twoends of the cylindrical body; moreover, the medical radiation apparatusfurther includes a couch plate capable of passing through the openingsdefined at both ends of the cylindrical body, so that the patient can bemoved to the radiation assembly to receive radiation treatment bydirectly moving the couch plate after the diseased tissue is positioned.The above technical solutions can avoid a body's motion after thediseased tissue being positioned until the patient being moved to theradiation assembly, and therefore a positioning error of the diseasedtissue caused by a body's motion is reduced and accordingly the accuracyof the radiation treatment thereafter is improved.

Further, the medical radiation apparatus includes a stator fixed to thecylindrical body, a rotor mounted on the stator, the rotor is rotatableabout a first axial direction, and the ray tube and the detector(together referred to as the imaging assembly) are mounted on the rotor.In the above technical solutions, during the operation of the imagingapparatus assembly, the orientations of the ray tube and the detectorfor imaging a diseased tissue are adjusted by rotating the rotor; whileduring the operation of the radiation assembly, the orientation of thetreatment head is adjusted by rotating the cylindrical body, i.e. theimaging assembly is rotatable independent of the radiation assembly,thereby reducing the chance that the imaging apparatus assembly and theradiation assembly interfere with each other.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a schematic view of the structure of a medical radiationapparatus according to some embodiments of the present disclosure;

FIGS. 2-3 are schematic views showing an operation of the medicalradiation apparatus according to some embodiments of the presentembodiment;

FIG. 4 is a schematic view of a three-dimensional (3D) structure of theinterior of the medical radiation apparatus according to someembodiments of the present disclosure;

FIG. 5 is a side view of the medical radiation apparatus in FIG. 4;

FIG. 6 is a 3D perspective view of the CT assembly in FIG. 1; and

FIG. 7 is a side view of the CT assembly in FIG. 6.

DETAILED DESCRIPTION

As described in the BACKGROUND, existing radiation therapy needs to usean imaging apparatus such as a CT scanner to position the diseasedtissue of a patient at first, and then the patient is moved to a linearaccelerator to receive a radiation treatment based on an image capturedfrom the imaging apparatus previously in which the diseased tissue ispositioned. The course during which the diseased tissue is positioned atfirst and then the patient is moved to the linear accelerator not onlyreduces the efficiency of the radiation treatment, but also results in apositioning error of the diseased tissue because the diseased tissue canmove due to the motion of the patient's body in the process of movingthe patient from the imaging apparatus to the linear accelerator, whichbrings about difficulties for radiation treatment.

Additionally, because many components in a radiation apparatus used in aradiation treatment, such as a medical linear accelerator, have largemasses which produce an overturning torque, the radiation therapyapparatus is further provided with counter balance weights so as toimprove the balance of the radiation therapy apparatus. However, itcause difficulty in installation, transport, calibration, andmaintenance to the medical radiation apparatus.

Therefore, the present disclosure provides a medical radiationapparatus, which includes an imaging assembly and a radiation assembly,and during a radiation treatment, the patient can be directly moved tothe radiation assembly by moving a couch plate to receive a radiationtreatment after the patient has been imaged and positioned in theimaging assembly. Thus, the chance of a poisoning error of the diseasedtissue caused by the motion of the patient is reduced, and the treatmentefficiency is improved. Additionally, the imaging assembly and theradiation assembly can constitute counter balance weights for each otherso that the overall volume and weight of the medical radiation apparatusare reduced, thereby reducing the difficulty in installation, transport,calibration, and maintenance to the medical radiation apparatus.

Next, take a CT assembly as an example of the imaging assembly, thetechnical solutions of the present disclosure is clearly and fullydescribed with reference to the drawings.

FIGS. 1-7 are structural schematic views of the medical radiationapparatus under different states according to some embodiments of thepresent disclosure.

Referring to FIG. 1, the medical radiation apparatus provided by thepresent embodiment includes a main frame, and a CT assembly 20 and aradiation assembly 30 both mounted on the main frame.

Specifically, the main frame includes a cylindrical body 10, the centralaxis of the cylindrical body 10 indicates a first axial direction. TheCT assembly 20 and the radiation assembly 30 are respectively positionedon an end of the cylindrical body 10 along the first axial direction.The CT assembly 20 and the radiation assembly 30 are served as counterbalance weights for each other, which improves the overall balance ofthe medical radiation apparatus.

Referring to FIGS. 2 and 3, in the present embodiments, the cylindricalbody 10 is a structure with openings defined in both ends, and themedical radiation apparatus further includes a movable couch plate 200.The movable couch plate 200 can move axially along the central axis ofthe cylindrical body 10, and can pass through the openings at both endsof the cylindrical body 10.

During an operation, as shown in FIG. 2, a patient 100 lies on themovable couch plate 200, and is moved from the opening in thecylindrical body 10 to the end of the CT assembly 20 to receive a CTscan, so as to acquire positioning images of the diseased tissue; then,as shown in FIG. 3, under the condition of keeping the body of thepatient 100 unmoved, the movable couch plate 200 is moved to theradiation assembly 30 to where a radiation treatment is performed basedon the acquired positioning images of the diseased tissue from the CTassembly 20.

Continuing to refer to FIGS. 1-3, in the embodiments, the radiationassembly includes a treatment head that is used for emitting radiationrays. The treatment head includes a series of components such as anaccelerating tube, an electron gun, movable targets, a magnet-deflectionsystem, a collimator, a flattening filter, a shielding layer, etc.,which are not repeated here.

The treatment head can axially rotate around the central axis of thecylindrical body 10, and radiation rays from the treatment head aretoward the interior of the cylindrical body 10. When an adjustment isperformed in a radiation treatment, the treatment head can rotate aroundthe patient so that the orientation of the radiation rays is adjusted.

In the present embodiments, the treatment head is fixed on thecylindrical body 10. The cylindrical body 10 is axially rotatable todrive the treatment head to axially rotate around the central axis ofthe cylindrical body 10.

Continuing to refer to FIG. 1, the medical radiation apparatus providedby the present embodiments further includes a base 40 for supporting thecylindrical body 10 thereon, and a roller driving mechanism arranged onthe base 40 for driving the cylindrical body 10 to axially rotate aroundthe central axis thereof.

Specifically, referring to FIG. 4 and FIG. 5, the roller drivingmechanism includes a second motor (not shown in the figure), a seconddriving wheel 60 coupled to the second motor, and a second driving belt61 wrapping around the second driving wheel 60 and the surface of thecylindrical body 10. In particularly, a driving belt groove 64 isdefined on the surface of the cylindrical body 10 around the centralaxis thereof, and the second driving belt 61 is engaged in the drivingbelt groove 64.

Further, referring to FIGS. 4 and 5, a plurality of guide wheels 63 witha same size or different sizes are mounted on the base 40, the surfacesof the guide wheels 63 press against the surface of the cylindrical body10, thereby reducing the friction the cylindrical body 10 is subject toduring the rotation of the cylindrical body 10 and improving therotation efficiency of the cylindrical body 10.

In the present embodiments, the CT assembly includes a ray tube and adetector that are respectively positioned on the opposite sides of thecentral axis of the cylindrical body 10 and opposing to each other. Asshown in FIG. 2, during a CT scan is performed to the patient 100, theray tube and the detector (not shown in FIG. 1) can rotate around thepatient 100 so as to adjust the imaging angle of the ray tube and thedetector of the CT assembly. One skilled in the art would readilyunderstand that, the above-mentioned ray tube and detector can bejointly referred to as an imaging assembly. Further, the medicalradiation apparatus further includes a rotor for mounting the imagingassembly, and the rotor is connected to the main frame so as to rotatealong with the main frame as the main frame rotates. An imagingthrough-hole is defined in the rotor and substantially coaxial with thecylindrical body 10. The imaging assembly can be located completely orat least partially within the interior of the main frame.

Specifically, referring to FIGS. 5, 6 and 7, in the present embodiments,the CT assembly includes a CT stator 51 and a CT rotor 54. The CT stator51 is fixed to the inner wall of the cylindrical body 10 via aconnecting plate 52, and thus the CT stator 51 can rotate along with thecylindrical body 10. The CT stator 51 has a through-hole 53 definedalong the central axis of the cylindrical body 10. As shown in FIG. 7,the CT stator 51 is connected with the rotor 54 via a connectingcomponent such as a bearing 23, and the rotor 54 is rotatable via thebearing 23 independent of the CT stator 51 and the cylindrical body 10.

The CT rotor 54 is mounted on the CT stator 51, a through-hole 55coaxial with the through-hole 53 is defined on the CT rotor 54 to allowthe object therein to be imaged, and the through-hole is substantiallycoaxial with the cylindrical body 10. The CT rotor 54 is movablyconnected to the CT stator 51 via a bearing so that the CT rotor 54 canrotate around the central axis of the cylindrical body 10.

Continuing to refer to FIGS. 6 and 7, the ray tube 74 and the detector75 constituting the imaging assembly are respectively mounted on the CTrotor 54 on the opposite sides of the through-hole 55. The ray tube 74and the detector 75 constituting the imaging assembly can rotate aroundthe through-hole 55 independent of the main frame. As shown in FIG. 1,the CT stator 51 and the CT rotor 54 are arranged completely within theinterior of the main frame. However, one skilled in the art wouldreadily understand that, the CT stator 51 and the CT rotor 54 also canbe arranged partially within the interior of the main frame.

Referring to FIGS. 2 and 3, the movable couch plate 200 can pass throughthe through-holes 53 and 55 and move the patient 100 to the positionbetween the ray tube 74 and the detector 75, the ray tube 74 and thedetector 75 are driven by the CT rotor 54 such that, through anadjustment for a CT scan, the ray tube 74 and the detector 75 arepositioned at an angle with respect to the patient.

In the present embodiments, the CT stator 51 of the medical radiationapparatus includes a CT driving mechanism for driving the CT rotor 54 torotate. The CT driving mechanism includes a first motor 76 coupled tothe CT rotor 54 and configured to drive the CT rotor 54 to rotate. TheCT driving mechanism can be directly fixed on the main frame, and thesesimple modifications fall within the protection scope of the presentdisclosure.

Specifically, for example, the CT driving mechanism can include a firstdriving wheel (not shown in the figures) fixedly coupled to the firstmotor 76, and a first driving belt (not shown in the figures) configuredto connect the first driving wheel and the CT rotor 54. During anoperation, the first motor 76 drives the first driving wheel to rotate,and drives the CT rotor 54 to rotate via the first driving belt.

In the present embodiments, the ray tube 74 and the detector 75constituting the imaging assembly can rotate around the imagingthrough-hole 55 independent of the main frame, and specifically, the CTrotor 54 of the CT assembly 20 is driven to rotate by the CT drivingmechanism, and then the ray tube 74 and the detector 75 are driven bythe CT rotor 54 to axially rotate around the central axis of thecylindrical body 10 so that CT scans from different orientations can beperformed to the patient 100 and the positioning images of the diseasedtissue are obtained; the cylindrical body 10 is driven by the rollerdriving mechanism to rotate around the central axis thereof, and thetreatment head of the radiation assembly 30 is driven by the cylindricalbody 10 to rotate around the central axis of the cylindrical body 10,and therefore a radiation treatment from different orientations can beperformed to the patient. That is, the CT assembly 20 and the radiationassembly 30 are operated via two sets of driving mechanisms, so theusage flexibility of the CT assembly 20 and the radiation assembly 30 isimproved, and the chance of interference between the CT assembly 20 andthe radiation assembly 30 is reduced.

Certainly, in embodiments other than the present embodiment, the raytube and the detector of the CT assembly can be directly fixed on theinner wall of the cylindrical body 10. In this way, the ray tube and thedetector of the CT assembly can be driven by the cylindrical body 10 torotate about the central axis of the cylindrical body 10, and thus therotation of the ray tube and the detector about the central axis of thecylindrical body 10 is implemented such that the imaging orientationwith respect to a patient can be adjusted in a CT scan. These simplemodifications fall within the protection scope of the presentdisclosure.

According to the above-mentioned embodiments of the present disclosure,the imaging apparatus of the medical radiation apparatus is described bytaking the CT imaging apparatus as an example. However, one skilled inthe art would readily understand that, other medical imaging equipment,for instance, Magnetic Resonance Image (MRI) System, Positron EmissionComputed Tomography (PET), (PET-CT), Single Photon Emission ComputedTomography (SPECT), and the like, can also be applied to the technicalsolutions disclosed in the present disclosure, and the above inventiveobject of the present disclosure can be obtained by integrating the mainframe thereof with the radiation treatment equipment, which is notrepeated here.

Although some preferable embodiments are disclosed as above, it is notintended to limit the technical solutions of the present disclosure.Without departing from the spirit and scope of the technical solutionsof the present disclosure, any person skilled in the art can implementany possible changes or modifications to the technical solutions of thepresent disclosure using the methods and technical contents disclosedabove, and thus, any simple changes and equivalent modifications to theabove embodiments according to technical essence of the presentdisclosure which does not depart from the technical solutions of thepresent disclosure, fall within the protection scope of the technicalsolutions of the present disclosure.

What is claimed is:
 1. A medical radiation apparatus comprising: a mainframe, rotatable about a central axis thereof, comprising a bodydefining openings on both ends thereof; a treatment head, connected withthe main frame and fixed to one end of the body, for emitting radiationrays; and an imaging assembly, connected with the main frame andpositioned on the other end of the body, for imaging an object, whereinduring a radiation treatment using the treatment head, at least a firstpart of the imaging assembly rotates along with the main frame when themain frame rotates, and during imaging of the object using the imagingassembly, at least a second part of the imaging assembly is rotatableindependent of the main frame.
 2. The medical radiation apparatus ofclaim 1, wherein at least the first part of the imaging assembly isfixed to the main frame.
 3. The medical radiation apparatus of claim 1,wherein the imaging assembly comprises a ray tube and a detector in anopposing arrangement, the ray tube and the detector are respectivelypositioned on opposite sides of a through-hole of the main frame.
 4. Themedical radiation apparatus of claim 3, wherein the ray tube and thedetector are mounted on the at least the second part of the imagingassembly.
 5. The medical radiation apparatus of claim 1, wherein the atleast the second part of the imaging assembly rotates around the centralaxis of the main frame.
 6. The medical radiation apparatus of claim 1,wherein the main frame comprises a cylindrical body.
 7. The medicalradiation apparatus of claim 6, wherein the main frame comprises a couchplate movable along a direction of the central axis to pass through theopenings defined on both the ends of the cylindrical body; and wherein athrough-hole is defined in the at least the second part of the imagingassembly along the direction of the central axis, and a ray tube and adetector are positioned on opposite sides of the through-hole, and thecouch plate is movable to pass through the through-hole.
 8. The medicalradiation apparatus of claim 1, wherein the at least the first part ofthe imaging assembly comprises a driving mechanism for driving the atleast the second part of the imaging assembly to rotate; and wherein thedriving mechanism comprises a first motor, a first driving wheel coupledto the first motor, and a first driving belt coupled between the atleast the second part of the imaging assembly and the first drivingwheel.
 9. The medical radiation apparatus of claim 1, wherein theimaging assembly is a Positron Emission Computed Tomography-ComputedTomography (PET-CT) assembly.
 10. The medical radiation apparatus ofclaim 1, wherein the imaging assembly is a Computed Tomography (CT)assembly.
 11. A medical radiation apparatus comprising: a main frame,rotatable about a central axis thereof, comprises a body definingopenings on both ends thereof; a treatment head, connected with the mainframe and fixed to one end of the body, for emitting radiation rays; anda Positron Emission Computed Tomography-Computed Tomography (PET-CT)assembly, connected with the main frame and positioned on the other endof the body, for imaging an object, wherein during a radiation treatmentusing the treatment head, at least a first part of the PET-CT assemblyrotates along with the main frame when the main frame rotates, andduring imaging of the object using the PET-CT assembly, at least asecond part of the PET-CT assembly is rotatable independent of the mainframe.
 12. The medical radiation apparatus of claim 11, wherein the atleast the first part of the PET-CT assembly is fixed to the main frame.13. The medical radiation apparatus of claim 11, wherein the PET-CTassembly comprises a ray tube and a detector in an opposing arrangement,the ray tube and the detector are respectively positioned on oppositesides of a through-hole of the main frame.
 14. The medical radiationapparatus of claim 13, wherein the ray tube and the detector are mountedon the at least the second part of the PET-CT assembly.
 15. The medicalradiation apparatus of claim 11, wherein the at least the second part ofthe PET-CT assembly rotates around the central axis of the main frame.16. The medical radiation apparatus of claim 11, wherein the main framecomprises a cylindrical body.
 17. The medical radiation apparatus ofclaim 16, wherein the main frame comprises a couch plate movable along adirection of the central axis to pass through the openings defined onboth the ends of the cylindrical body; and wherein a through-hole isdefined in the at least the second part of the PET-CT assembly along thedirection of the central axis, and a ray tube and a detector arepositioned on opposite sides of the through-hole, and the couch plate ismovable to pass through the through-hole.
 18. The medical radiationapparatus of claim 11, wherein the at least the first part of the PET-CTassembly comprises a driving mechanism for driving the at least thesecond part of the PET-CT assembly to rotate; and wherein the drivingmechanism comprises a first motor, a first driving wheel coupled to thefirst motor, and a first driving belt coupled between the at least thesecond part of the PET-CT assembly and the first driving wheel.
 19. Amedical radiation apparatus comprising: a main frame, rotatable about acentral axis thereof, wherein the main frame comprises a body definingopenings on both ends thereof; a couch, movable form a first position toa second position along the central axis, for supporting an object; atreatment head, connected with the main frame, for emitting radiationrays and fixed to one end of the body; and an imaging assembly,connected with the main frame and positioned on the other end of thebody, for imaging the object, wherein during a radiation treatment usingthe treatment head, the couch is located at the first position, andduring imaging of the object using the imaging assembly, the couch islocated at the second position, at least part of the imaging assembly isrotatable independent of the main frame.
 20. The medical radiationapparatus of claim 19, wherein the imaging assembly is a PositronEmission Computed Tomography-Computed Tomography (PET-CT) assembly.